This invention relates to a method of regulating the growth of plants, principally to a method of protecting plant life from injury due to frost or sub-freezing temperatures using various ammonium imines.
It is common knowledge that frost and sub-freezing temperatures can have serious, and sometimes permanent injurious effects on plants. This is, of course, particularly important in crop production, and each year there are tremendous losses in both vegetable and fruit production due to frost damage. For example, frost may have a particularly severe effect on peach production; entire crops of growing peaches have been eliminated by frost or freezing conditions. Other fruit crops that are particularly susceptible to frost include apples, strawberries and pears.
However, it is not only fruit crops that are damaged by frost; vegetable and cereal crops may suffer in the same way. Sugar beets and tomatoes are examples of vegetable crops which are particularly susceptible to damage at freezing and sub-freezing temperatures.
The damage caused by frost and sub-freezing temperatures does not always result in the killing of crops and plants, and often results in only a partial injury thereto. This injury can, however, have serious consequences, particularly in horticultural and agronomic crops. For example, a late spring frost can cause lopsided fruit and russeting in apple crops, while corn subjected to frost in its early stages of development, may also be severly injured.
At present there is little effective protection that can be afforded to plants on a commercial scale. Simple and inexpensive methods of protection have been sought for some time.
The simplest, mechanical means of protection that have been used in the past involved covering the plants with a layer of insulation. This insulating layer can be a sheet of material such as paper or plastics. However, this method is of very limited effectiveness, and is clearly impractical for large areas of crops, or indeed individual crops of large size - such as fruit trees.
Other insulating layers that have been used, particularly to protect fruit trees, include smoke, fogs and foams. Again these methods have a very limited use and effectiveness, and fogs and smoke are clearly impractible if it is windy. Moreover, in recent years the use of smoke for such purposes has become unacceptable because of resulting air pollution.
A number of chemical methods have also been tried over the years, and the following list contains examples of such methods:
U.S. Pat. No. 2,185,663 utilizes an emulsion of petroleum oil and water carrying a simple alcohol;
U.S. Pat. No. 2,610,117 utilizes a plant hormone mixed with a substance having anti-pellagric activity and a substance having vitamin K activity;
U.S. Pat. No. 3,045,394 utilizes a polymer of N-vinyl-2-pyrrolidone in a non-phytotoxic carrier;
U.S. Pat. No. 3,120,445 utilizes a mixture of hydrated lime, bentonite clay, and water;
U.S. Pat. No. 3,129,529 utilizes a coating of an emulsion of wax dissolved in an organic solvent of petroleum hydrocarbons and a surface active agent;
U.S. Pat. No. 3,555,727 utilizes aqueous sugar beet molasses;
U.S. Pat. No. 3,578,679 describes the use of N,N-dimethyldecenylsuccinamic acid; N-dimethylamino-decenyl-succinamic acid; and N-dimethylamino-decenylsuccinimide; and
U.S. Pat. No. 3,867,126 describes the use of 3,6-dioxo-4-pyridazine acetic acid derivatives.
However, to date these methods have not provided an entirely satisfactory solution to the problem of protecting plant life from frost.